Parallel Ice Sheet Model (PISM)

The Parallel Ice Sheet Model (PISM) is an open-source modelling framework for ice sheets and glaciers. It is parallel, thermodynamically-coupled and capable of high resolution. PISM has been widely adopted as a tool for doing science.

Development of PISM is supported by NASA grants 20-CRYO2020-0052 and 80NSSC22K0274 and NSF grant OAC-2118285.

Graphic: J. Garbe

PISM was used in several studies that contributed to major advances in the understanding and model representation of key physical processes which control the behavior of ice sheets, for example:

• Basal sliding: Bueler et al. (2009)
• Energy conservation: Aschwanden et al. (2012)
• Ice-front motion: Albrecht et al. (2011)
• Calving: Levermann et al. (2012)
• Fracture dynamics: Albrecht and Levermann (2012)
• Sub-shelf melt: Reese et al. (2018)
• Surface melt: Zeitz et al. (2021)
• Marine ice-cliff instability (MICI): Schlemm et al. (2022)

Sea-level projections

Source: Edwards et al. (2021)

The ice sheets on Greenland and Antartica are the largest freshwater reservoirs with a combined sea-level rise potential of more than 65 meters. Their mass loss and future contributions to sea-level rise in response to different scenarios of changing atmospheric and oceanic conditions can be estimated by applying PISM, as previously accomplished by e.g.:

• Antarctica
  • ISMIP6: Seroussi et al. (2020)
  • LARMIP-2: Levermann et al. (2020)
  • Reese et al. (2020)
  • Winkelmann et al. (2015)
  • SeaRISE: Nowicki et al. (2013a)
• Greenland
  • ISMIP6: Goelzer et al. (2020)
  • Aschwanden et al. (2019)
  • SeaRISE: Nowicki et al. (2013b)
• Both ice sheets
  • Edwards et al. (2021)
  • Golledge et al. (2019)
  • Winkelmann and Levermann (2013)
  • SeaRISE: Bindshadler et al. (2013)

Glacial cycle simulations

Source: Albrecht et al. (2020b)

Long-term model simulations are helpful for the reconstruction of the glacial-interglacial history of the Earth's ice sheets. This contributes to a better understanding of dynamic threshold behavior and sea-level change in the past but also in the future. For the Antarctic Ice Sheet, an ensemble of glacial-cycle simulations in order to constrain paleo parameter sensitivities and boundary conditions has, for example, been performed using PISM by:

• Albrecht et al. (2020a), Albrecht et al. (2020b)

Long-term stability of ice sheets

Source: Modified after Garbe et al. (2020)

Several positive and negative feedback mechanisms may impact the stability of ice sheets on long timescales. Examples include the positive surface-melt-elevation feedback or the negative isostatic solid-Earth rebound effect. When crossing critical thresholds, irreversible ice loss may follow. The overall effect of the interplay between various feedback mechanisms in the long term has been assessed in the following studies using PISM, among others:

• Garbe et al. (2020)
• Golledge et al. (2017)
• Clark et al. (2016)
• Feldmann and Levermann (2015)
• Golledge et al. (2015)
• Winkelmann et al. (2015)

Coupling to other Earth system components

Source: Modified after Zwally et al. (2015)

Ice sheets interact with other Earth system components, such as the atmosphere or the ocean. To take into account and study related feedback mechanisms as well as their effect on the dynamics of the Greenland and Antartic ice sheets, PISM has been coupled to other Earth system components:

• Ocean
  • Potsdam Ice-shelf Cavity mOdel (PICO): Reese et al. (2018)
  • PISM-MOM: Kreuzer et al. (2021)
• Atmosphere
  • dEBM-simple: Zeitz et al. (2021), Garbe et al. (2023)
• Solid-Earth
  • Lingle-Clark: Bueler et al. (2007)
  • PISM-VILMA (work in progress)

Model intercomparisons

PISM has participated in numerous model intercomparison projects (MIPs). For a complete list, please see MIPs & Collaborations.

Support

If you are looking for help with PISM, feel free to join the PISM workspace on Slack. You can also contact the developers team directly or write an e-mail to uaf-pism@alaska.edu.

Contributing

Bug reports, contributions of code, documentation, and tests are always appreciated. Please see the PISM manual for instructions.